TRACT 34.

GUNNERY EXPERIMENTS.

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"with the 1st, 2d, and 3d guns, the charges which give thegreatest velocities, are nearly as follow, viz.

Gun n° 1 at the charge of 12 oz,

2---- - 14 oz,

3 ----- 16 oz.

Here it will not be so proper to specify what portionof the weight of the ball these weights of powder are; beingno ways regulated by that circumstance; but what portionof the bore of the gun is filled with these quantities of pow-der. Now, by the table of the lengths of charges in Art.104, it appears that the lengths of the charges of 12, 14,and 16 oz, are these, viz.

12 oz - - 8'20 inches; gun 1, its length 28‘5,

14 oz - - 9'47 inches ; gun 2 - - - 38*4,

10 oz - - 10 - 74 inches ; gun 3 - - - 57'7.

Then dividing each length of charge by its correspondinglength of gun, we obtain nearly these three following frac-tions, viz.

TT5- in gun 1 of 15 calibers long,

£ or *rr in gun 2 of 20 calibers long,

T? bt gun ^ of 30 calibers long,

which express what part of the bore is filled with powder,when the greatest velocity is given to the ball, with each ofthese lengths of gun. And which therefore is not one andthe same constant part for all lengths of gun, but varyingnearly in the reciprocal subduplicate ratio of the length ofthe bore ; or still nearer in the reciprocal subduplicate ratioof the empty part of the bore before the charge. / nil, bythis rule, finding the part for the longest gun, or n° 4, itwill he found to be nearly or 12 inches in length, answer-ing- to 18 ounces of powder. So that the whole set ofnumbers, for the greatest velocity, will be as follows;